1 files changed, 74 insertions, 0 deletions
diff --git a/examples/quickcontrols/spreadsheets/Spreadsheets/spreadformula.cpp b/examples/quickcontrols/spreadsheets/Spreadsheets/spreadformula.cpp
new file mode 100644
index 0000000000..87a961f40c
--- /dev/null
+++ b/examples/quickcontrols/spreadsheets/Spreadsheets/spreadformula.cpp
@@ -0,0 +1,74 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "spreadformula.h"
+#include "datamodel.h"
+#include "spreadkey.h"
+#include "spreadrole.h"
+#include "spreadmodel.h"
+
+bool Formula::includesLoop(SpreadModel *model, const DataModel *dataModel, QSet<int> *history) const
+{
+    if (m_operator == Operator::Invalid)
+        return false;
+
+    if (history == nullptr) {
+        QSet<int> history;
+        return includesLoop(model, dataModel, &history);
+    }
+
+    if (m_operator == Operator::Sum) {
+        SpreadKey top_left = dataModel->getKey(m_cellIds.first);
+        SpreadKey bottom_right = dataModel->getKey(m_cellIds.second);
+        if (bottom_right.first < top_left.first)
+            std::swap(top_left.first, bottom_right.first);
+        if (bottom_right.second < top_left.second)
+            std::swap(top_left.second, bottom_right.second);
+        for (int row = top_left.first; row <= bottom_right.first; ++row) {
+            for (int column = top_left.second; column <= bottom_right.second; ++column) {
+                const int id = dataModel->getId(SpreadKey{row, column});
+                if (history->find(id) != history->end())
+                    return true;
+                const QString edit_text = dataModel->getData(id, spread::Role::Edit).toString();
+                const Formula formula = model->parseFormulaString(edit_text);
+                if (!formula.isValid())
+                    continue;
+                auto it = history->insert(id);
+                if (formula.includesLoop(model, dataModel, history))
+                    return true;
+                auto cit = spread::make_const(*history, it);
+                history->erase(cit);
+            }
+        }
+    } else {
+        const int id_1 = m_cellIds.first;
+        if (history->find(id_1) != history->end())
+            return true;
+        const QString edit_text = dataModel->getData(id_1, spread::Role::Edit).toString();
+        const Formula formula = model->parseFormulaString(edit_text);
+        if (!formula.isValid())
+            return false;
+        auto it = history->insert(id_1);
+        if (formula.includesLoop(model, dataModel, history))
+            return true;
+        auto cit = spread::make_const(*history, it);
+        history->erase(cit);
+
+        if (m_operator != Operator::Assign) {
+            const int id_2 = m_cellIds.second;
+            if (history->find(id_2) != history->end())
+                return true;
+            const QString edit_text = dataModel->getData(id_2, spread::Role::Edit).toString();
+            const Formula formula = model->parseFormulaString(edit_text);
+            if (!formula.isValid())
+                return false;
+            auto it = history->insert(id_2);
+            if (formula.includesLoop(model, dataModel, history))
+                return true;
+            auto cit = spread::make_const(*history, it);
+            history->erase(cit);
+        }
+    }
+
+    return false;
+}